Corrugator for metal tubing



April 14, 1964 R. c. ANDERSEN 3,128,821

CORRUGATOR FOR METAL TUBING Original Filed Feb. 12, 1959 s Sheets-Sheet 1 @m/m C. Mme;

April 14. 1964 R. c. ANDERSEN CORRUGATOR FOR METAL TUBING 3 Sheets-Sheet 2 Original Filed Feb. 12, 1959 April 14, 1964 RJC. ANDERSEN 3,128,821

vCORRUGATOR FOR METAL TUBING Original Filed Feb. 12, 1959 5 Sheets-Sheet 5' INVENTOR.

d/zaZeme/Z United States Patent 3,128,821 CGRRUGATQR FUR METAL TUBING Raymond C. Andersen, deceased, iate of Lombard, Iil., by Jessie K. ieterson, administratrix, Lombard, llL, assignor to Flexonies Corporation, Maywood, Ill, a corporation of Illinois Continuation of application Ser. No. 792,753, Feb. 12, 1959. This application Mar. 5, 1962, Ser. No. 179,277 '7 Claims. (Cl. 153-7 1) This invention relates generally to apparatus for helically corrugating metal tubing and more particularly to apparatus that is especially useful for helically corrugating stainless steel tubing.

This application is a continuation of copending application Serial No. 792,792, which was filed February 12, 1959, and now abandoned.

According to conventional practice, helically corrugated tubing made from straight-walled tubing is formed by means of a helically configurated die plate which is rotated about the tubing. When such apparatus is used on stainless steel tubing, difiiculties have been encountered with seizing of the die plate and the tubing. Additionally, twisting or deforming of the tube is known to occur because of the considerable pressure exerted by the die plate.

Other prior art devices have employed outwardly disposed and inwardly converging angulated rollers. However, this latter approach does not result in easy flow of the metal of the tubing into corrugations. As a consequence, there are tendencies for the tooling to sever the tubing.

Therefore, an important object of the present invention is to provide an improved apparatus for helically corrugating metal tubing.

Another object of the present invention is to provide improved apparatus for helically corrugating stainless steel tubing.

Yet another object of the present invention is to provide a corrugator for metal tubing in the use of which the metal of the tubing flows easily into corrugations.

A further object of the invention is to provide a corrugator for metal tubing which minimizes seizing of the tubing and the forming dies.

Still further objects and features of the invention pertain to the particular structure and arrangements whereby the above objects are attained.

The invention, both to its structure and mode of operation, will be better understood by reference to the following disclosure and drawings forming a part thereof wherein:

PEG. 1 is a schematic side view of a corrugator for metal tubing arranged in accordance with the present invention;

PEG. 2 is a side view of the tubing and the die rings employed in the corrugator of FIG. 1, the die rings being shown in simplified form to facilitate description;

FIG. 3 is a bottom view of one pair of die rings mounted in their carrier; and

FIG. 4 is an elevational view, partially broken away, of the mechanism shown in FIG. 3.

Referring now in detail to the drawings, specifically to PEG. 1, there will be seen a corrugator for metal tubing constructed in accordance with a preferred embodiment of the invention, including a first stage forming station and a second stage forming station 12. In other embodiments of the invention a single forming station has proved adequate while in still other embodiments more than two stages have proved useful.

Forming station 11') is comprised of a motor 14 fastened to a base 16 which, in turn, is secured to a floor 18. A pair of forming dies, specifically annular die ring 20 3,128,821 Patented Apr. 14, 1964 and annular die ring 22, is mounted in the carrier generally shown at 24 to be freely rotatable therein. The carrier 24 is comprised of a fixture or frame 26 that is rotatably mounted to the base 16 as by means of the shaft 28 and the bearings 3i), rotation of the frame 26 being achieved by means of the pulley 32 and the drive belt 34 which is associated with motor 14.

Since forming station 12 is comprised similarly to forming station 10, like elements of the station 12 have been designated by like numerals to which have been added the sufiix a.

With further reference to FIG. 1, the leading end 4% of the tubing 42 may advantageously be supported on a truck 44 which is provided with jaws 46 for gripping the tubing 42 so as to prevent rotation thereof. Truck 44 may travel along floor 18 or may be adapted to ride freely on tracks 47 disposed therein. The trailing end of tubing 42 may likewise be supported by a truck similar to the truck 44 or by other suitable means.

According to the showing of FIG. 1, tubing 42 is held unrotatable with respect to the truck 44 while the carriers 24 and 24a are rotated about the tubing. In certain instances, it has proved convenient to hold the carriers 24 and 24a stationary while rotating the tubing, as by drive means carried on the truck 44.

It will be noted from the showing of FIG. 2, that die ring 20 and die ring 22 are angled transversely to the direction of tubing movement which is indicated by the arrow 48. This angulation of the die rings serves to cooperate with the distance that the die ring 24) is apart from the die ring 22 in determining the pitch of the grooves or corrugations formed in the tubing 42. Furthermore, die ring 20 and die ring 22 are radially loaded or offset in diametrically opposite directions in order to create shear in the tubing 42 and thereby urge the formation of the grooves or corrugations. The extent of this radial loading of ring 20 with respect to ring 22 controls, to a large degree, the depth of the groove which is produced. It has also been found that the shearing created by the rings 20 and 22 is also affected by the ratio of the inside diameter of the rings to the outside diameter of the tubing, the radius on the inside diameter or working edge of the die rings, the thickness of the tubing, and the required pitch of the corrugations.

It will be apparent that, as the die rings 20 and 22 are rotated about the tubing 42 as by means of motor 14, the tubing 42 will be fed along in the direction indicated by the arrow 48. Thus, as the tubing 42 passes from the rings 20 and 22, it will have had formed therein a first pass groove or corrugation 5%. in like manner, after the tubing 42 has passed from the rings 26a and 22a, it will have had formed therein a second pass groove or corrugation 52. Second pass groove 52 represents the finished corrugations which are desired in the tubing 42. Advantageously, die rings 2% and 22 are rotated in the same direction as the die rings 20a and 22a.

Turning now to FIGS. 3 and 4, the frame 26 is shown to include an end plate 54 aflixed to the pulley 32 and an end plate 56 spaced apart from end plate 54 by a top plate 58 and a bottom plate 6i). In order to properly support the tubing which is being corrugated, end plate 54 has aflixed thereto a guide bushing 62 which is appropriately provided with a number of radial and thrust bearings 64. in like manner, end plate 56 has afiixed thereto a guide bushing 65 which is appropriately provided with a number of radial and thrust bearings 68. Guide bushing 66, being thus arranged, is adapted to cooperate with guide bushing as in supporting the tubing 4-2.

Suitable means are provided for mounting the die rings 2% and 22 to the frame 26. The means for mounting die ring 29 include a pivot assembly 7% which is fastened to the top plate 58 and to which a bracket '72 3 is secured. Advantageonsly, die ring 26 is mounted in the inner race of a bearing unit 74 which is carried by the bracket 72. Die ring 2%) is mounted so as to be freely rotatable within the bearing unit 74; and to this end, roller bearings 76 are appropriately inclined in order to accept both thrust and radial loading.

The means for mounting die ring 22 to the frame 26 include the plate 73 which is mounted to the bottom plate 60 and which carries the pivot assembly 89. Further, a bracket 82 which is adapted to carry a bearing unit 84 is suitably fastened to bottom plate 60. Unit 84 carries roller bearings 86 appropriately inclined in order to accept both thrust and radial loading. Die ring 22 is mounted in the inner race of bearing unit 34 to be freely rotatable therein.

In order to vary the spacing, the angulation, and the loading of the die rings 2%) and 22, there is provided a system of locking screws, screw links and appropriate slots for adjusting the position of brackets 72 and 82 within the frame 26. For example, by means of the screw links 90, plate 78 may be adjusted longitudinally in the frame 26 within the confines established through guides 92 and 94 which are fastened to plate 78 and slidably contact plate 69. Such an adjustment would result in changing the spacing between the die rings 24 and 22 and accordingly the pitch of the corrugations produced in the tubing. Conveniently, the slots 96, 98 and 1% are incorporated in the plate 69 in order to implement this adjustment.

Additionally, when looking screws 1G2, 103 and 1 34 are loosened in their threaded engagement with plate 73, bracket 32 may be rotated about pivot assembly 80 by action of the screw link 1% in order to adjust the angulation and loading of ring 22. Link 196 passes through an unthreaded bore in the block 10$ which is securely mounted to the plate 73. Link 106 threadedly engages a post 109 which is pivotally fastened to the ear of circular plate 110. So that bracket 82 and plate 110 with which it is associated may thus be freely rotated by means of link 106, arcuate slot H2 in plate 110 and arcuate slots 114 and 116 in bracket 82 are advantageously provided.

Bracket 72, unlike bracket 82, is arranged for arcuate adjustment only. Accordingly, bracket 72 is affixed to a plate 120 which may be rotated by means of the screw link 122. Link 122 is secured to the plate 58 by means of the block 124 through whose unthreaded bore it passes. Link 122 threadedly engages a post 125 which is piovtally affixed to the ear of circular plate 126. Cooperating in this adjustment are the locking screws 126, 128 and 130 which threadedly engage plate 58, as well as the arcuate slot 132 which is disposed in plate 120 and the arcuate slots 134 and 136, which slots are disposed in bracket 72.

The operation of the corrugator of the present invention will be apparent from the above descriptions.

The specific example herein shown and described is illustrative only. Various changes in structure will, no doubt, occur to those skilled in the art; and these changes are to be understood as forming a part of this invention insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. Apparatus for helically corrugating metal tubing comprising:

(a) a first annular die ring adapted to encompass the tubing, a portion of the inner periphery of said first die ring indentably bearing on the exterior of said tubing in a substantially radial direction;

(b) a second annular die ring adapted to encompass said tubing axially spaced-apart from said first die ring, a portion of the inner periphery of said second die ring indentably bearing upon the exterior of said tubing in a different, substantially radial direction;

(0) means supporting said first and second die rings for free rotation thereof; and

(d) means incurring relative rotation between said tubing and said die rings whereby to displace said tubing axially and whereby to form a helical corrugation in said tubing.

2. Apparatus for helically corrugating metal tubing comprising:

(a) a first annular die ring adapted to encompass the tubing, a portion of the inner periphery of said first die ring indentably bearing on the exterior of said tubing in a radial direction;

([1) a second annular die ring adapted to encompass said tubing axially spaced-apart from said first die ring by a distance equal to the pitch of the helical corrugation to be formed in said tubing, a portion of the inner periphery of said second die ring indentably bearing on the exterior of said tubing in a dif ferent radial direction;

(0) means supporting said first and said second die rings for free rotation thereof; and

(d) means incurrim relative rotation between said tubing and said die rings whereby to displace said tubing axially and whereby to form a helical corrugation in said tubing.

3. Apparatus for helically corrugating metal tubing comprising:

(a) a first annular die ring adapted to encompass the tubing, a portion of the inner periphery of said first die ring indentably bearing on the exterior of said tubing in a radial direction, the inside diameter of said first die ring being substantially greater than the outside diameter of said tubing;

(b) a second annular die ring adapted to encompass said tubing axially spaced-apart from said first die ring by a distance equal to the pitch of the helical corrugation to be formed in said tubing, a portion of the inner periphery of said second die ring indentably bearing on the exterior of said tubing in a different radial direction, the inside diameter of said second die ring being substantially greater than the outside diameter of said tubing;

(0) means supporting said first and said second die rings for free rotation thereof; and

(d) means incurring relative rotation between said tubing and said die rings whereby to displace said tubing axially and whereby to form a helical corrugation in said tubing.

4. Apparatus for helically corrugating metal tubing 0 according to claim 1 wherein said means supporting the die rings further supports each of said rings at an angle relative to the diametral plane of said tubing.

5. Apparatus for helically corrugating metal tubing according to claim 1 wherein the inner peripheries of said first and said second die rings bear on the exterior of said tubing in diametrically opposite directions.

6. Apparatus for helically corrugating metal tubing according to claim 1 and further comprising at least one additional pair of annular die rings constructed, adapted and arranged as said first and said second die rings whereby to deepen and reduce the pitch of the corrugation formed by said first and said second die rings.

7. A corrugator for metal tubing comprising:

(a) support means including a truck riding freely on a track and carrying means for gripping said tubing;

(12) a stationary base aligned with said support means;

(c) a frame rotatably mounted to said base, including a top plate, a bottom plate and end means interconnecting said top and bottom plates;

(d) guide means for said tubing mounted on said end means;

(e) a first bracket adjustably mounted to said frame by a pivot and locking screws which pass through slots formed in said bracket threadedly to engage the top plate of said frame;

(f) a first angularly disposed, annular die ring mounted in said first bracket to be freely rotatable about said tubing, a portion of the inner periphery of saidfirst die ring indentably bearing on the exterior of said tubing in a radial direction;

(g) a second bracket adjustably mounted to said frame by a pivot, a longitudinally adjustable plate slidably disposed between said second bracket andsaid bottom plate, locking screws extending through longitudinal slots in the bottom plate of said frame engaging said longitudinally adjustable plate, and screw links operative between said frame and said longitudinally adjustable plate;

(11) a second angularly disposed, annular die ring mounted in said second bracket to be freely rotatable about said tubing and to be adjustably spaced-apart from said first die ring along the axis of said tubing by said screw links, a portion of the inner periphery of said second die ring indentably bearing on the exterior of said tubing in a different radial direction; and

(i) drive means affixed to said base for rotating said frame, whereby to displace said tubing axially and whereby to form a helical corrugation on said tubing.

References Cited in the file of this patent UNITED STATES PATENTS 1,045,092 Mark et al. Nov. 19, 1912 FOREIGN PATENTS 750,485 Germany Ian. 15, 1945 201,252 Australia Feb. 1, 1955 204,056 Australia Feb. 1, 1955 218,154 Australia Aug. 25, 1958 

1. APPARATUS FOR HELICALLY CORRUGATING METAL TUBING COMPRISING: (A) A FIRST ANNULAR DIE RING ADAPTED TO ENCOMPASS THE TUBING, A PORTION OF THE INNER PERIPHERY OF SAID FIRST DIE RING INDENTABLY BEARING ON THE EXTERIOR OF SAID TUBING IN A SUBSTANTIALLY RADIAL DIRECTION; (B) A SECOND ANNULAR DIE RING ADAPTED TO ENCOMPASS SAID TUBING AXIALLY SPACED-APART FROM SAID FIRST DIE RING, A PORTION OF THE INNER PERIPHERY OF SAID SECOND DIE RING INDENTABLY BEARING UPON THE EXTERIOR OF SAID TUBING IN A DIFFERENT, SUBSTANTIALLY RADIAL DIRECTION; (C) MEANS SUPPORTING SAID FIRST AND SECOND DIE RINGS FOR FREE ROTATION THEREOF; AND (D) MEANS INCURRING RELATIVE ROTATION BETWEEN SAID TUBING AND SAID DIE RINGS WHEREBY TO DISPLACE SAID TUBING AXIALLY AND WHEREBY TO FORM A HELICAL CORRUGATION IN SAID TUBING. 